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Abstract Hydrogel nanophotonic devices exhibit attractive tunable capabilities in structural coloration and optical display. However, current hydrogel‐based tunable strategies are mostly based on a single physical mechanism, and it remains a challenge to merge multiple mechanisms for active devices with integrated functionalities. Here, a hydrogel metagrating combining Fabry‐Pérot (FP) resonance and diffraction effects is proposed for achieving tunable absorption and dynamic wavelength‐selective beam steering. Through exploiting hydrogel shrinkage under electron‐beam exposure, a hydrogel nanocavity composed of Ag/Hydrogel/Ag three‐layer films can be directly printed with arbitrary patterns, enabling the direct‐pattering technique of metagrating. The hydrogel nanocavity performs as an FP‐type absorber, and its absorption peak rapidly shifts with humidity variation due to the hydrogel layer scaling. The response speed is 150 nm. It is further demonstrated that the hydrogel metagrating exclusively deflects light at the resonance wavelength, and its operating wavelength can be actively switched by regulating ambient humidity. The proposed tunable hydrogel metagrating can promote new technologies of tunable metasurfaces for optical filtering, gas sensing, and optical imaging.

We investigate unconventional magnon blockade (UMB) in a dissipative photon–magnon coupling cavity, where the coherent and dissipative coupling between photon and magnon can be adjusted by the position of the yttrium iron garnet sphere in the cavity. An approximate analytical solution for the statistical property of magnon is provided, which is in good agreement with the results obtained by numerically solving the Lindblad master equation. Our results indicate that UMB can be achieved in the case of dissipative photon–magnon coupling, but not in the case of coherent photon–magnon coupling. Secondly, by adjusting the amplitude of the external laser field, dynamic control of UMB can be achieved. Finally, by solving the Lindblad master equation containing the occupation number of thermal magnon and photon, the statistical properties of magnons will transition from nonclassical to classical. It is shown that the above phenomena originate from the interference between different quantum paths. Our research may provide theoretical possibilities for quantum manipulation schemes at the single-magnon level and open up a new avenue for designing single-magnon sources in a dissipative photon–magnon coupling system.

We propose an efficient scheme to enhance the generation of optical second-order sidebands (OSSs) in an atom-assisted optomechanical system. The cavity field is coupled with a strong driving field and a weak probe field, and a control field is applied to the atom. We use the steady-state method to analyze the nonlinear interaction in the system, which is different from the traditional linear analysis method. The existence of an auxiliary three-level atom driven by the control field significantly enhances the generation of an OSS. It is found that the efficiency of the OSS can be effectively modulated by adjusting the Rabi frequency of the control field, optomechanical cooperativity and atomic coupling strength. Our scheme provides a promising solution for controlling light propagation and has potential application in quantum optical devices and quantum information networks.

To efficiently manipulate parametric mode mixing is an intriguing physical issue for phonon-cavity electromechanics, which is also crucial for various technological applications ranging from frequency synthesis to nonlinear spectroscopy. Here, we theoretically investigate the dependence of phononic high-order sidebands on intra- and inter-mode couplings in two interconnected electromechanical resonators. When the system operates in a strong inter-mode coupling regime, we report that two inter-mode phonon-scattering pathways allow us to selectively obtain either odd- or even-order sidebands at different output ports. The signal intensities of the separated sidebands can be independently modulated by introducing harmonic actuation forces acting on the interconnected resonators. Once the intra-mode coupling becomes totally dominant, the direct transition between intra-mode phonons only triggers the emergence of full-order sidebands in the nonlinear responses. In this case, increasing the quality factor of the resonators is beneficial for amplifying a few low order sidebands nearby the principal modes of the resonators but sacrificing the order of the sidebands.

We theoretically propose a scheme to measure the topological charge (TC) of a mid-infrared vortex beam via observing the intensity distribution of the four-wave mixing (FWM) field in an asymmetric semiconductor double quantum well. Due to the existence of Fano-type interferences, the special inherent interference takes place, and thus generates the interference-type phase and intensity patterns for the FWM field. Furthermore, it is demonstrated that the intensity and visibility of the interference-type intensity pattern can be drastically manipulated by adjusting the intensity and detuning the control field. Subsequently, we perform the TC measurement of the vortex driving field via directly monitoring the number of light spots of the FWM field. By choosing the suitable control parameters, the detectable value of the TC can reach to 120 with the visibility exceeding 0.97. Our scheme may provide the possibility for the realization of a mid-infrared OAM detector in a compact solid-state system.

We propose an effective scheme to enhance the efficiency of optical second-order sideband (OSS) via optomechanically induced absorption (OMIA) in a double-cavity optomechanical system. In this double-cavity optomechanical configuration, the optomechanical cavity is driven by a strong control field and a weak probe pulse, while the assisted cavity is excited by another strong control field. Using experimentally achievable parameters, we identify that the present optomechanical system can create the OMIA effect and improve the efficiency of the upper OSS beyond that is achieved by employing optomechanically induced transparency (OMIT). With the aid of OMIA, we also report that the maximum efficiency and linewidth of the upper OSS peak can be modulated by the double-cavity coupling strength and the detuning of the driving field. The present proposal offers a new path to optimize optical nonlinearity and design chip-scale signal processing.

A scheme for the coherent control of perfect optical vortex (POV) in an asymmetric semiconductor double quantum well (SDQW) nanostructure is proposed by exploiting the tunneling-induced highly efficient four-wave mixing (FWM). The orbital angular momentum (OAM) is completely transferred from a unique POV mode to the generated FWM field. Using experimentally achievable parameters, we identify the conditions under which resonant tunneling allows us to improve the quality of the vortex FWM field and engineer helical phase wave front beyond what is achievable in the absence of resonant tunneling. Furthermore, we find that the intensity and phase patterns of the vortex FWM field are sensitive to the detuning of the probe field but rather robust against the detuning of the coupling field. Subsequently, we perform the coaxial interference between the vortex FWM field and a same-frequency POV beam and show interesting interference properties, which allow us to measure the topological charge of the output POV beam. Our result may find potential applications in quantum technologies based on POV in solids.

We propose a potentially practical scheme for realizing ultrasensitive size sensor of a single metallic nanoparticles (MNP) in a hybrid nonlinear microcavity. This is achieved by exploiting a well-established microcavity-engineered plasmonic resonance, where a degenerate parametric amplifier (DPA) is embedded into the microcavity driven by a strong pump field and a weak probe pulse. It is shown that the transmission spectrum of the probe pulse exihibits a two-peak splitting and the splitting width depends on the radius. The radius of a single MNP can be inferred from the transmission spectrum by monitoring the width between two peaks. Using experimentally achievable parameters, we identify the detection sensitivity of the sensor can reach approximately 0.198 THz/nm for detecting and sizing of individual MNPs as small as 10 nm in radius.

Abstract We analyze the destructive interference in monolayer graphene under Landau quantization in a time-dependent way by using the Bloch-Maxwell formalism. Based on this analysis, we investigate the dynamics control of an infrared probe and a terahertz (THz) switch pulses in graphene. In presence of the THz switch pulse, the destructive interference take places and can be optimized so that the monolayer graphene is completely transparent to the infrared probe pulse. In absence of the THz switch pulse, however, the infrared probe pulse is absorbed due to such a interference does not take place. Furthermore, we provide a clear physics insight of this destructive interference by using the classical dressed-state theory. Conversely, the present model may be rendered either absorbing or transparent to the THz switch pulse. By choosing appropriate wave form of the probe and switch pulses, we show that both infrared probe and THz switch pulses exhibit the steplike transitions between absorption and transparency. Such steplike transitions can be used to devise a versatile quantum interference-based solid-state optical switching with distinct wave-lengths for optical communication devices.

Cu2ZnSnS4 (CZTS) and Cu2ZnGeS4 (CZGS) nanoparticles are important inorganic hole transport layers (HTLs) for carbon electrode-based perovskite solar cells (C-PSCs). However, the performances of the corresponding C-PSCs are still not satisfactory, which mainly originates from the un-optimized photoelectronic properties of the pristine CZTS and CZGS nanoparticles. Herein, composition engineering via alloying CZTS and CZGS is used to optimize the photo-electronic properties of the resulting CZGxT1−xS HTLs (x = 0, 0.25, 0.50, 0.75, and 1.0), and when combined with a FA1−xMAxPbI3−yBry active layer, the performance of the C-PSCs was greatly increased. The optimum HTL of CZG0.5T0.5S exhibits a suitable conduction band energy barrier at the perovskite/CZG0.5T0.5S interface, and thus, charge carrier recombination at the perovskite/CZG0.5T0.5S interface is effectively suppressed. However, the CZG0.5T0.5S HTL exhibited much greater conductivity, which efficiently transported the holes from the perovskite to a carbon electrode. This resulted in C-PSCs with the CZG0.5T0.5S HTL demonstrating a champion power conversion efficiency of 19.8%. [ABSTRACT FROM AUTHOR]

A scheme of enhanced Goos-Hänchen (GH) shifts in reflected and transmitted light beams is exploited in a cavity, where an asymmetric double AlGaAs/GaAs quantum well structure with resonant tunneling to a common continuum is employed as the intracavity medium. With the help of Fano-type interference induced by resonant tunneling, the generated GH shifts that contain a negative lateral shift in reflected light beam and a positive lateral shift in transmitted light beam are found to be significantly enhanced. More interestingly, these GH shifts in reflected and transmitted light beams are modulated by means of a control beam and external bias voltage, in which maximum negative shift of 1.86mm and positive shift of 0.37mm are achievable. [ABSTRACT FROM AUTHOR]

We investigate the light propagation and dynamical control of a weak pulsed probe field in asymmetric double quantum wells via Fano interference, which is caused by tunneling from the excited subbands to the same continuum. Our results show that the system can produce anomalous and normal dispersion regions with negligible absorption by choosing appropriate coupling strength of the tunneling and the Fano interference. Interesting enough, the dispersion can be switched between normal and anomalous by adjusting the relative phase between the pulsed probe and coherent control fields owing to the existence of the perfectly Fano interference. Thus, the relative phase can be regarded as a switch to manipulate light propagation with subluminal or superluminal. The temporal and spatial dynamics of the pulsed probe field with hyperbolic secant envelope are analyzed. [ABSTRACT FROM AUTHOR]

We theoretically study the ultrafast transfer of a single electron between the ground states of a coupled double quantum dot (QD) structure driven by a nonlinear chirped few-cycle laser pulse. A time-dependent Schrödinger equation without the rotating wave approximation is solved numerically. We demonstrate numerically the possibility to have a complete transfer of a single electron by choosing appropriate values of chirped rate parameters and the intensity of the pulse. Even in the presence of the spontaneous emission and dephasing processes of the QD system, high-efficiency coherent transfer of a single electron can be obtained in a wide range of the pulse parameters. Our results illustrate the potential to utilize few-cycle pulses for the excitation in coupled quantum dot systems through the nonlinear chirp parameter control, as well as a guidance in the design of experimental implementation. [ABSTRACT FROM AUTHOR]

We propose a scheme for controlling the coherent transport of a single electron through a closed three-level structure in coupled quantum dots. The coherent transport is externally controlled by applying a weak few-cycle pulse with an adjustable carrier-envelope phase (CEP). It is revealed numerically that there exists a significant dependence of the electron transport on the CEP. Our results illustrate the potential to utilize few-cycle pulses for the excitation in coupled quantum dot systems through control of the CEP, as well providing guidance in the design for possible experimental implementations. [ABSTRACT FROM AUTHOR]

We theoretically investigate the simultaneous formation and stable propagation of slow optical soliton pairs in semiconductor quantum dots with a four-level biexciton-exciton cascade configuration. Owing to the destructive interference set up by two continuous wave control fields that couple to a biexciton state, the linear as well as nonlinear dispersion can be dramatically enhanced simultaneously with the absorptions of two weak probe fields being almost suppressed. These results reveal that the detrimental distortions of the two weak-pulsed probe fields due to dispersion effects can be well balanced by the self-phase modulation effect under very low input light intensity, which leads to the slow temporal optical soliton pairs with matched group velocity and amplitude. We also show that the propagation of slow optical solitons can be strongly modified by the biexciton coherence. [ABSTRACT FROM AUTHOR]

We propose and analyze an efficient scheme for suppressing the absorption of a weak probe field based on intersubband transitions in a four-level asymmetric coupled quantum well (CQW) driven coherently by a probe laser field and a control laser field. We study the steady-state process analytically and numerically, and our results show that the probe absorption can be completely eliminated under the condition of Raman resonance (i.e. two-photon detuning is zero). Besides, we can observe one transparency window without requiring one- or two-photon detuning to exactly vanish. This investigation may provide a possible scheme for EIT in solids by using the CQW. [ABSTRACT FROM AUTHOR]

We perform a time-dependent analysis of continuous wave (cw) four-wave mixing (FWM) in InGaAs/AlAs coupled double quantum well (CDQW) structures via intersubband transitions. By using the coupled Schrodinger-Maxwell approach, we obtain the corresponding explicit analytical expressions for the input probe and FWM-generated signal fields. We calculated the dependencies of the efficiency of the FWM-generated fields on cw pump fields and the depths of penetration into the CDQW sample. Such a nonlinear optical process may be used to generate coherent short-wavelength radiation efficiently in the CDQW solid state system. [ABSTRACT FROM AUTHOR]

We propose a practical scheme for one-way quantum computing based on efficient generation of 2D cluster state in thermal cavities. We achieve a controlled-phase gate that is neither sensitive to cavity decay nor to thermal field by adding a strong classical field to the two-level atoms. We show that a 2D cluster state can be generated directly by making every two atoms collide in an array of cavities, with numerically calculated parameters and appropriate operation sequence that can be easily achieved in practical Cavity QED experiments. Based on a generated cluster state in Box(4) configuration, we then implement Grover’s search algorithm for four database elements in a very simple way as an example of one-way quantum computing. [ABSTRACT FROM AUTHOR]

We propose a scheme for high-precision two-dimensional (2D) atom localization via the four-wave mixing (FWM) in a four-level double- atomic system. Due to the position-dependent atom-field interaction, the 2D position information of the atoms can be directly determined by the measurement of the normalized light intensity of output FWM-generated field. We further show that, when the position-dependent generated FWM field has become sufficiently intense, efficient back-coupling to the FWM generating state becomes important. This back-coupling pathway leads to competitive multiphoton destructive interference of the FWM generating state by three supplied and one internally generated fields. We find that the precision of 2D atom localization can be improved significantly by the multiphoton destructive interference and depends sensitively on the frequency detunings and the pump field intensity. Interestingly enough, we show that adjusting the frequency detunings and the pump field intensity can modify significantly the FWM efficiency, and consequently lead to a redistribution of the atoms. As a result, the atom can be localized in one of four quadrants with holding the precision of atom localization. [ABSTRACT FROM AUTHOR]

We study the control of high-precision three-dimensional (3D) atom localization by measuring the population of the excited state in a ladder-type three-level atomic system driven by a weak probe field and a control field, together with three mutually perpendicular standing-wave fields. We find that the precision of 3D atom localization in volumes depends sensitively on the frequency detuning of the probe field and the intensity of the control field. Most importantly, we show that adjusting the phase shifts associated with the standing-wave fields leads to a redistribution of the atoms and a significant change of the atomic coherence, so that the atom can be localized in volumes that are substantially smaller than a cubic optical wavelength. [ABSTRACT FROM AUTHOR]

A scheme of enhanced four-wave mixing (FWM) signal is exploited in graphene under an external magnetic field via multiphoton quantum destructive interference. By solving the coupled Schrödinger–Maxwell formalism, a time-dependent analysis performs the integrated analytical expressions of the input probe pulse and generated FWM field. Taking into account the tunable optical transition frequency between the Landau levels (LLs) in graphene, it is found that the generated FWM signal in the infrared region can be significantly enhanced and its efficiency is nearly . As a result, the proposed magnetised graphene system may provide a striking potential for generating long-wavelength radiation. [ABSTRACT FROM AUTHOR]

We investigate high-order harmonic generation in a metallic-nanoparticle–quantum-dot hybrid system. Driven by a moderate electric field intensity Guassian-shape few-cycle pulse which is chirped by a hyperbolic-tangent-form carrier envelope phase, the hybrid system can generate extreme-ultraviolet super-continuum harmonics (13.3 eV maximal photon energy) and isolated ultrashort pulses ( FWHM). Numerical simulation results reveal that the plasmonic field enhancement could extend the cutoff order and continuum region in harmonic spectra. The extension effect by plasmonic enhancement could be well understood theoretically by the semi-classical two-level atom model. [ABSTRACT FROM AUTHOR]